<!DOCTYPE html>
<html>
<head>
  <title></title>
</head>
<body>
<div id="app">target element</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2.5.16/dist/vue.min.js"></script>
<script type="text/javascript">
  let vm = new Vue({
    el: '#app',
    template: '<h1>template element</h1>' // 模板节点将替换原有DOM节点
  })
</script>
</body>
</html>